How to complete the local authority code on an SDLT form
Local authority codes on SDLT forms
HMRC says a paper SDLT1 needs a valid local authority code in question 29. The code identifies the authority area containing the lead property.
- Use HMRC’s code list.
- For land across a boundary, either code can be used.
- HMRC prefers the authority covering most of the property.
- Check historic authority names for older or late returns.
Scroll down for the full analysis.
Read the original guidance here:
How to complete the local authority code on an SDLT form
When you complete a stamp duty land tax return, HMRC asks for a local authority code. On a paper SDLT1, this is question 29. HMRC says you must give a valid code or it will reject the return. The key is to identify the council area for the lead property.
What this rule is about
A land transaction return must be in the required form and contain the required information that the rules prescribe for the transaction concerned. That is the legal framework. The local authority code is one item of information that HMRC’s form asks for.
This is an easy box to miss. Even so, it can prevent HMRC from accepting a paper return.
The code is not simply the name of your present council. HMRC’s list contains codes for old councils too. This matters if you file a return late or local government boundaries have changed.
What the official source says
HMRC’s manual says that, from 1 October 2014, anyone filing a paper SDLT1 must enter a valid local authority code. It identifies the field as question 29 on paper SDLT1 and question 1.29 online. HMRC says you must answer the question.
- Use the code for the local authority area in which the lead property is situated.
- If the property crosses a boundary, either local authority code can be entered.
- HMRC prefers the code for the authority containing most of the property.
- Use HMRC’s local authority code list rather than guessing from a council name.
- Former authorities remain in the list for late notification of an older transaction.
- If a new authority does not appear in HMRC’s list after a change, HMRC says you should use the code for the authority that existed before it. Follow that instruction.
The same manual guidance applies to question 2 on form SDLT3 and question 10 on form SDLT4.
This is HMRC guidance about completing its forms. It is not a separate tax rule set by the manual. The law requires the return to contain prescribed information; HMRC’s manual explains how it wants this field completed.
What this means in practice
Start with the property, not the council you deal with for council tax or waste collection. The question asks about the lead property. Check its location and then match that location to the code in HMRC’s list.
If there is one property and it lies wholly within one council area, with no land or title extending across a boundary, the answer should usually be straightforward. Usually, it is. The difficulty tends to arise with land, farms, large plots and titles that cross a boundary.
- Check the property address and title plan before the return is sent.
- Find the local authority in HMRC’s code list.
- Copy the number carefully into the right question.
- For a paper SDLT1, do not leave question 29 blank.
- For SDLT3, check question 2.
- For SDLT4, check question 10.
- Keep a note of why that code was chosen if the site crosses a boundary.
There is a separate point about where SDLT applies. HMRC’s source says SDLT stopped applying to land transactions in Scotland from April 2015. It also says Land Transaction Tax applies to Welsh land transactions from 1 April 2018. This page concerns the SDLT forms used for England and Northern Ireland.
How to analyse it
Work through the question in a simple order. Do not begin by searching for the newest-looking council name. First establish the property location and the date that matters.
- Is this an SDLT return for a transaction in England or Northern Ireland?
- Which property is the lead property for the form?
- Which local authority area contains that property?
- Does the property lie wholly within that area?
- If not, which authority contains most of it?
- Has the relevant local authority since merged or been reorganised?
- Does HMRC’s list show the former authority rather than the new one?
- Have you entered the code in the correct question for the form being used?
What if the property sits on a boundary? Do not assume that makes the form impossible to complete. HMRC says you may use either code. It prefers the authority covering most of the property.
Example
Sam is completing a paper SDLT1 for a property wholly in the Adur area. HMRC’s list gives Adur the code 3805. Sam enters 3805 in question 29.
Now change one fact. Part of the garden is across the boundary in another local authority area, but most of the house and land are in Adur. HMRC’s manual says either code can be used where the garden crosses into another local authority area, although it prefers Adur’s code because most of the property falls there. Sam can use Adur.
There is no tax calculation in this example. The point is simply to give HMRC the location code that its form asks for.
Why this can be difficult in practice
A council name on a recent letter may fail to appear in HMRC’s list when the authority has changed, merged or been reorganised since the relevant transaction. That can happen. This does not always mean the list is wrong. The source explains that it keeps historic authorities for older transactions and late returns.
You might think the current council is always the answer. Where a new authority is absent from its list after a change, HMRC says you should use the authority that existed before that change. Use the earlier authority.
- A current council name may differ from the name in HMRC’s historic list.
- A property postcode may not show that land crosses a council boundary.
- The house may be in one area while part of the land is in another.
- Different SDLT forms put the field in different question numbers.
- A blank or invalid code on a paper SDLT1 may lead HMRC to reject the return.
- Old transactions need the authority that was relevant at the effective date, not necessarily today’s authority.
The source page is also an HMRC manual page, not a live form checker. Form names, question numbers and code lists can change. Check HMRC’s current materials before filing, especially if you are using a paper or historic form.
Key takeaways
- Enter a valid local authority code when HMRC’s SDLT form asks for one.
- Use the authority covering the lead property, not a guessed council name.
- For a boundary site, HMRC prefers the authority covering most of the property.
Technical analysis
For advisers, and for anyone who wants to check the law behind this page. You do not need this section to understand the guidance above.
Legislation
- FA 2003 Schedule 10 para 1 — required form and information for SDLT returns
Official guidance
The pages below are HMRC’s guidance. Guidance is not law. It sets out how HMRC reads the legislation, and it is not binding on you, on a tribunal or on a court. Where guidance and the legislation differ, the legislation wins. HMRC can also change or withdraw guidance, and it may not cover your facts.
Where this is not settled
- The supplied HMRC manual page may not reflect the current availability, numbering or online design of SDLT forms.
- The supplied statutory text is recorded only up to 17 November 2025. Current form requirements and codes should be checked against HMRC’s live materials before filing.
Evidence you would need
This kind of case is decided on the facts of the individual property. These are the records that usually settle it, and the ones an adviser would ask you for.
- The address and plan for the lead property
- A map or other evidence if the property crosses a local authority boundary
- The transaction’s effective date where the council has changed or merged
- The current HMRC form and local authority code list
Explore this with an AI
Readers often want to test their own situation. Copy the prompt below into ChatGPT, Claude or Gemini. It hands the model the actual legislation for this page rather than letting it answer from memory, and tells it to be explicit about what is uncertain. What comes back is information, not advice – check it against the links above.
I am researching UK Stamp Duty Land Tax (SDLT), which applies in England and Northern Ireland. MY QUESTION How to complete the local authority code on an SDLT form [Replace this with your own situation: what you are buying, the price, the dates, who the buyer is, and what you plan to do with the property.] THE LAW THIS TURNS ON - FA 2003 Schedule 10 para 1 - required form and information for SDLT returns https://www.legislation.gov.uk/ukpga/2003/14/schedule/10/paragraph/1/2025-11-17 HMRC's guidance page on this topic (guidance, not law): https://www.gov.uk/hmrc-internal-manuals/stamp-duty-land-tax-manual/sdltm62320 HOW I WANT YOU TO ANSWER 1. Work from the legislation above. Read it before answering. HMRC guidance is HMRC's view of the law, not the law, and does not bind a tribunal or a court. 2. Tell me what the rule actually requires, in plain English. 3. Tell me which facts decide the answer, and which facts would change it. 4. Tell me what evidence I would need to support the position. 5. Be explicit about anything unsettled or fact-sensitive. Do not guess. 6. Your training data has a cutoff and SDLT rates and reliefs change at fiscal events. Say so if you are not sure the law is current. POINTS ALREADY KNOWN TO BE UNCERTAIN ON THIS TOPIC - The supplied HMRC manual page may not reflect the current availability, numbering or online design of SDLT forms. - The supplied statutory text is recorded only up to 17 November 2025. Current form requirements and codes should be checked against HMRC's live materials before filing. Do not give me a conclusion you cannot support from the provisions above.
Legislation links show Finance Act 2003 as it stood on 2025-11-17. The law may have changed since, and the rules that apply are those in force on the date of your transaction. The official guidance this page is based on is here.
This page was last updated on 1 September 2026
Useful article? You may find it helpful to read the original guidance here: How to complete the local authority code on an SDLT form
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